Incidence of Myocarditis Associated with Diphtheria, Tetanus, and Pertussis Vaccine: A Rare Case Series.

Myocarditis induced by diphtheria-tetanus-pertussis (DTP) vaccination is extremely rare, accounting for only two cases thus far. Hence, to supplement knowledge regarding its pathogenesis and treatment, we reported two cases of myocarditis associated with DTP vaccination in adults. Two patients (a 40-year-old female and a 43-year-old male) presented with mild symptoms and were hemodynamically stable. In both patients, the DTP vaccination was given 4 and 6 days before admission. Both patients had prolonged corrected QT interval (QTc), poor left ventricular function, and high troponin levels at admission. However, numerous ST segment depression was only noted in the first case. Bacteriology and virology study results were negative for any pathogen. No atherosclerotic lesions were observed by coronary angiography. Cardiac magnetic resonance imaging was only performed in the second case, which confirmed the diagnosis of myocarditis. Initial therapy was administered with a beta-blocker, angiotensin-converting enzyme inhibitor, and intravenous methylprednisolone. Nonetheless, in the first case, rapid clinical deterioration and sudden cardiac death occur within 3 days of hospitalization. Learn from the first case, a high-dose intravenous immunoglobulin (IVIG) treatment was initiated in the second case, which resulted in an improvement in left ventricular function and clinical symptoms, as well as a significant reduction in QTc interval and troponin levels. Rapid diagnostic testing and early recognition of the fulminant course is mandatory, allowing clinicians to aggressively treat the patient with high-dose intravenous immune globulin, thus obtaining a better outcome.